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• The Fe-Cr-Ni-Mn-N austenitic stainless steel exhibits an exceptional mechanical property at 4.2 K with a high yield strength of 1.5 GPa. • The deformation nanotwinning, HCP ε-martensite transformation, dislocation slip with L -C locks and stacking fault formation which provided a marked contribution to the Fe-Cr-Ni-Mn-N alloy's ultrahigh strain hardening rate and outstanding strength at liquid helium temperature 4.2 K. • The Fe-Cr-Ni-Mn-N austenitic stainless steel displays outstanding cryogenic mechanical properties through a progressive synergy of deformation mechanisms leading to exceptional strength which provides a new insight into the commercialized development of high-performance alloys for cryogenic applications. We report the mechanical performance and microstructural characteristics of a Fe-Cr-Ni-Mn-N alloy at cryogenic temperatures. The exceptionally high yield strength of 1.5 GPa combined with a high strain-hardening rate and no deterioration in ductility at 4.2 K was displayed. The evolution of deformation microstructure was examined using electron backscatter diffraction (EBSD), the transmission Kikuchi diffraction (TKD), high-resolution transmission electron microscopy (HRTEM), and aberration-corrected scanning TEM (STEM). The deformation microstructure mainly consisted of dislocation slip with L -C locks, {111} stacking fault formation, {111} deformation nanotwinning, and FCC → HCP shear transformation at 4.2 K. The occurrence of FCC-HCP shear transformation inside/near {111} twins to form γ-γ tw -ε dual-phase structure induces a dynamic Hall-Petch effect that promotes the strain-hardening rate and enhances the strength-ductility combination. We believe that this alloy displays outstanding damage tolerance through a progressive synergy of deformation mechanisms leading to exceptional strength which provides a new insight into the commercialized development of high-performance alloys for cryogenic applications. [Display omitted] [ABSTRACT FROM AUTHOR]

• 316 L powder and 17–4PH powder are mixed in different mass ratios to fabricate five types of stainless steels by directed energy deposition (DED) technique. • In the range of 0–70%, with the increase of 17–4PH powder content, the anisotropy and grain size of DED stainless steel are significantly reduced, and the mechanical properties are greatly improved. • P70 shows the weakest anisotropy and the best mechanical properties, which can be attributed to the cyclic phase transformation under cyclic reheating treatment and the multi-stage transformation-induced plasticity (TRIP) effect over a wide range of strains, respectively. Owing to the special layer-by-layer deposition process of directed energy deposition (DED), columnar coarse grains, produced by cyclic reheating with intrinsic directional heat flow along the building direction, are difficult to avoid. These grains result in strong anisotropic characteristics with poor mechanical properties, which restrict the application of DED products. This work proposes a novel fabrication strategy based on the cyclic-phase-transformation behavior, which can reduce the anisotropy and improve the mechanical properties of DED-printed stainless steel. Using this fabrication strategy, 316 L powder (austenitic stainless steel) and 17–4PH powder (martensitic stainless steel) were mixed in different mass ratios to fabricate five types of DED-printed stainless steels. Among the five samples, P70 (mixture of 70 wt% 17–4PH powder and 30 wt% 316 L powder) showed the weakest anisotropy and the best mechanical properties, which can be attributed to the cyclic phase transformation under cyclic reheating treatment and the transformation-induced plasticity (TRIP) effect over a wide range of strains, respectively. Compared with the pure 316 L printed material, the tensile test results of P70 showed that the yield strength (YS) and ultimate tensile strength (UTS) increased by 35.4% and 34.5%, respectively, whereas the uniform elongation (UE) and total elongation (TE) were improved by 63.9% and 31.4%, respectively. In addition, the strength–ductility balance (UTS × UE) increased by as much as 120.4%. The proposed fabrication strategy is expected to reduce the anisotropy in other materials that undergo cyclic-phase-transformation phenomena during additive manufacturing. [ABSTRACT FROM AUTHOR]

• The δ-ferrite of I and A + I existed 〈100〉 and 1/2<111> dislocation loops. • Thermal aging accelerated the hardening of irradiated δ-ferrite. • Irradiation did not accelerate the hardening of thermally aged δ-ferrite. • The interaction can promote G-phase precipitation. • The interaction can cause δ-ferrite hardening, which is mainly affected by spinodal decomposition and G-phase. In the harsh service environment of high temperature and intense neutron irradiation in water-cooled nuclear reactors, the austenitic stainless steel weld overlay cladding on the inner surface of the reactor pressure vessel suffers from thermal aging and irradiation damage simultaneously, which can induce microstructural evolution and hardening of the material. Since it is quite difficult to achieve this simultaneous process out of the pile, two kinds of combined experiments, i.e., post-irradiation thermal aging and post-aging irradiation were performed on 308 L stainless steel weld metals in this work. The interactive effect of thermal aging and proton irradiation on microstructural evolution and hardening of δ-ferrite in 308 L weld metal was investigated by combining atom probe tomography, transmission electron microscopy and nanoindentation tests. The results revealed that thermal aging could eliminate the dislocation loops induced by irradiation and affect the phase transition process by accelerating spinodal decomposition and G-phase precipitation, thus enhancing hardening of irradiated δ-ferrite. For the effect of irradiation on the microstructure and hardening of thermally aged δ-ferrite, however, intensive collision cascades can intensify G-phase precipitation and dislocation loop formation but decrease spinodal decomposition, leading to a limited effect on hardening of thermally aged δ-ferrite. Furthermore, the interaction of thermal aging and irradiation can promote G-phase precipitation. Meanwhile, the interaction can cause δ-ferrite hardening, which is mainly influenced by spinodal decomposition, followed by G-phase and dislocation loops, where spinodal decomposition and G-phase cause hardening by inducing strain fields. [Display omitted] [ABSTRACT FROM AUTHOR]

• Dissimilar laser welding of CrMnFeCoNi high entropy and 316N austenitic stainless steel was performed. • The ultimate strength of the welded joints is 510 MPa at room temperature and 820 MPa at 77 K, which can reach ∼90 % of the base materials at both room and cryogenic temperatures. • The dominant deformation mechanism was mainly twinning during the plastic deformation which accounting for the higher tensile strength, especially at cryogenic temperature. • The sound welded joints between CrMnFeCoNi high entropy and 316N austenitic stainless steel can be considered for cryogenic applications. The microstructure and mechanical properties of dissimilar laser beam welded joint between CrMnFeCoNi alloy and 316LN stainless steel was investigated. The results showed that the defect-free dissimilar joint was obtained by laser beam welding. The ultimate strength of the welded joints can reach ∼90% of the base materials at both room and cryogenic temperatures. The deformation substructure mainly consisted of planar dislocation, the stacking faults and the dissociation of stacking faults into nanotwins. The volume fraction of the nanotwins was increasing at cryogenic temperature. The hardness fluctuates greatly in welded joint and the lowest hardness was located at fusion zone near the fusion line. The fracture of the welded joint was located at the fusion zone in consistence with the lowest hardness area. It is mainly attributed to the coarse grain and stress concentration at this area. [Display omitted] [ABSTRACT FROM AUTHOR]

• Grain refinement decreases the intrinsic mechanical stability of austenite in transformation-induced plasticity steels. • The essence of austenite mechanical stability is the competition between martensite transformation and dislocation slip. • The influence of grain size on the stress for dislocation slip is more obvious than that for martensite transformation. • The yielding mechanism of austenite transits from dislocation slip to martensite transformation with the refinement of austenite grains. An austenitic stainless steel was employed to clarify the effect of grain size on the intrinsic mechanical stability of austenite in transformation-induced plasticity (TRIP) steels. Contrary to the general impression in TRIP-assisted steels with multi-phase microstructure, grain refinement decreases the mechanical stability of austenite in the single-phase austenitic steel. The unexpected phenomenon was explained in the essence of austenite mechanical stability by theoretical calculation and experimental verification: dislocation slip and martensite transformation are two competing deformation mechanisms during plastic deformation of austenite, the stress for martensite transformation will be lower than that for dislocation slip when the grain size is smaller than a critical value. Therefore, the yielding mechanism of austenite will transit from dislocation slip to martensite transformation with the refinement of austenite grains. [Display omitted] [ABSTRACT FROM AUTHOR]

• The feasibility of the double-sided welding approach to join N40 has been established. • The welds possessed high strength and joint efficiency. • There was no evidence of sensitization in the HAZ of the weldments. • The welds contained lower amount of δ ferrite leading to improved magnetic response. • The FSW approach yielded superior weldments relevant for application in tokamak devices. Nitrogen containing austenitic stainless steels (N-ASS) are widely utilized to fabricate various structural components in tokamak type fusion reactors owing to their suitable mechanical and functional properties. These components are exposed to a range of temperatures (4–500 K) and interact closely with the magnetic fields that are used to control and contain the plasma within the tokamak systems. Nitronic-40 (N40) or XM-11 stainless steel is one such N-ASS used for fabricating structural components in the magnetic and vacuum vessel systems in tokamak devices. Fabrication of most of the larger components in the magnetic and vacuum vessel systems typically involves some type of fusion-based welding process. This study presents a double-sided friction stir welding (FSW) approach as an alternative to fusion welding processes to join 12 mm thick N40 plates to obtain joints with a low fraction of δ ferrite (a detrimental ferromagnetic phase), high joint efficiency, no sensitization and loss of hardness in the heat affected zone, and minimal nitrogen desorption from the weld nugget. The double-sided FSW approach yielded superior weldments when compared to similar joints accomplished by fusion welding for application in tokamak devices. [Display omitted] [ABSTRACT FROM AUTHOR]

• First atomic-scale investigation of cryogenic deformation mechanisms in 316 L SS. • Nucleation of α′ involves formation of transition zone due to dislocation shuffle. • As α′ grows into γ, the OR between α′ and γ changes by lattice bending. • Stacking faults and twins can also serve as nucleation sites for α′. Liquefied natural gas storage and transportation as well as space propulsion systems have sparked interest in the martensitic transformation and behaviours of 316 L stainless steels (SS) under ultra-cryogenic deformation. In this study, high-resolution transmission electron microscopy (HRTEM) and molecular dynamics (MD) simulations were used to investigate the atomic arrangements and crystalline defects of deformation-induced γ-austenite → ε-martensite → α′-martensite and γ → α′ martensitic transformations in 316 L SS at 15 and 173 K. The γ → ε transformation involves the glide of Shockley partial dislocations on (111) γ planes without a change in atomic spacing. The formation of an α′ inclusion in a single ε-band is achieved by a continuous lattice distortion, accompanied by the formation of a transition zone of α′ and the expansion of the average atomic spacings due to dislocation shuffling. As α′ grows further into γ, the orientation relationship (OR) of the α′ changes by lattice bending. This process follows the Bogers-Burgers-Olson-Cohen model despite it not occurring on intersecting shear bands. Stacking faults and twins can also serve as nucleation sites for α′ at 173 K. We also found that direct transformation of γ → α′ occurs by the glide of 6 a γ [ 11 2 ¯ ]/12 dislocations on every (111) γ plane with misfit dislocations. Overall, this study provides, for the first time, insights into the atomic-scale mechanisms of various two-step and one-step martensitic transformations induced by cryogenic deformation and corresponding local strain, enhancing our understanding of the role of martensitic transformation under ultra-cryogenic-temperature deformation in controlling the properties. [Display omitted] [ABSTRACT FROM AUTHOR]

The article discusses Furniss & White, a British steel foundry pioneering the use of N'GENIUS Series high strength austenitic stainless steels. Topics discussed include the partnership with N'GENIUS Materials, the alloy's performance in cryogenic applications with enhanced strength and corrosion resistance, and the company's growth in industries such as oil and gas, defense, and clean energy.

India's first Vande Bharat Sleeper trainset was launched by Minister for Railways Ashwini Vaishnaw at the BEML rail complex in Bengaluru. The trainset, manufactured in just nine months, is a significant achievement for BEML. It is constructed from austenitic stainless steel and equipped with advanced safety features, meeting stringent fire safety standards. The trainset offers a world-class passenger experience with amenities such as USB charging ports, security systems, modular pantries, and accessible facilities. Minister Vaishnaw expressed enthusiasm for the trainset, stating that it will provide a world-class travel experience for Indian Railways passengers. [Extracted from the article]

Cryospain, a leading company in cryogenic engineering, addresses the issue of hydrogen embrittlement, which is a critical concern across multiple industries. Hydrogen embrittlement occurs when hydrogen infiltrates certain metals, making them brittle and prone to fracture. Various factors contribute to hydrogen embrittlement, including specific types of corrosion. Preventing hydrogen embrittlement requires key mitigation strategies such as choosing materials less susceptible to embrittlement, applying protective coatings, implementing hydrogen removal strategies, and adopting preventive design strategies. Cryospain offers expertise and services to help companies prevent hydrogen embrittlement and mitigate its risks. [Extracted from the article]

An off-axis stepped hole containing a steel stop rod and a magnet passes through the transverse hole containing the locking rod (Fig.4a). Photo.22 shows (left to right) the locking rod, magnet, retaining pin and stop rod ready for final assembly. On the drill press bore the longitudinal clearance hole for the magnet so that it intersects with the locking rod hole close to its end (Photo.21). The magnet and steel stud used in the positioned rod mechanism are therefore not needed. [Extracted from the article]

The article explores the versatility and cost-effectiveness of replaceable-insert spade drills across various industries and production settings. These drills offer benefits such as reduced cycle time and overall cost per hole, making them ideal for high-production runs and enabling machinists to quickly change out worn inserts.

• By introducing high-temperature DIC analysis, the PLC effect in an austenitic stainless steel was investigated. • Serration type dynamically changed even at an applied strain rate at temperatures from 473 to 623 K. • The dynamic type transition of serrated flow obeyed the variation in PLC band nucleation and propagation behavior. • The spatial-temporal coupling effect plays an important role in the microscopic nucleation manner of the PLC band. In order to further understand high-temperature deformation behavior and its-related mechanical properties, the Portevin–Le Chatelier (PLC) effect in an Fe–19Cr–13Ni–0.2C austenitic stainless steel was investigated using high-temperature digital image correlation (DIC) analysis. Under the tensile testing at temperatures from 473 to 623 K, different types of serrated flow appeared even at a constant applied strain rate, and the type transition took place dynamically in a certain order with deformation time. DIC analysis revealed that the dynamic type transition of the serrated flow obeys the PLC band propagation behavior, and that the transition of the PLC band propagation behavior could be attributed to the PLC band nucleation manner. Numerical modeling also proved that the nucleation manner of PLC band nucleation is determined by the spatial-temporal coupling effect. [ABSTRACT FROM AUTHOR]

Researchers at the Federal Institute of Education have conducted a study on high-nitrogen austenitic stainless steel used in orthopedic implants. The study focused on the competition between work hardening, dynamic recovery, and dynamic recrystallization during thermomechanical processing. Results indicated a high activation energy for hot deformation and a direct competition between work-hardened and recrystallized grains. The research concluded that the stacking fault energy and fine precipitates influence the grain boundary mobility during the competition. [Extracted from the article]

A recent study from the Ocean University of China explores the impact of solution treatment on the intergranular corrosion behavior of 316L stainless steel fabricated through selective laser melting (SLM). The research highlights the importance of heat treatment in optimizing the organizational structure and reducing residual stress in SLM-316L stainless steel. The study found that solid solution treatment led to a decrease in intergranular corrosion performance, with changes in the type of oxide particles and the structure of intergranular corrosion. This research provides valuable insights into enhancing the performance of SLM-316L stainless steel in demanding conditions. [Extracted from the article]

• Tribocorrosion test conducted under continuous and intermittent sliding. • Wear rate increased at intermittent tribocorrosion process. • Repeated sliding promoted the grain refinement and regenerated passive film. • Periodical removal of the solid passive film enhanced the abrasive wear. In this research, the tribocorrosion behavior of 316L stainless steel in simulated seawater was investigated under continuous and intermittent sliding at open circuit potential. The tribocorrosion mechanism was discussed in terms of wear morphologies, mechanical property as well as chemical composition. Meanwhile, microstructure evolution inside the wear track and open circuit potential recorded after sliding were analyzed to quantify the repassivation kinetics and evaluate the impact of the regenerated passive film on wear. The results showed that the wear rate increased under intermittent sliding when the pause time is long enough to repassivate after sliding. Repeated sliding promoted the refinement of the grain inside the sliding area, which was beneficial to the generation of the thicker and more compact passive film inside the wear track. The ruptured passive film often acted as abrasives during subsequent sliding. Therefore, the accelerated material loss under intermittent sliding was attributed to the periodic mechanical removal of the thickened passive film and the enhanced abrasive wear inside the wear track. [ABSTRACT FROM AUTHOR]

• δ-ferrite could introduce a deflected crack path at δ/γ interface in the solution treated sample, which significantly increases the fatigue crack growth resistance. • The reticular M 23 C 6 precipitated in decomposed δ-ferrite after accelerated aging process is responsible for the microcrack nucleation in the crack tip plastic zone. • The preexisting microcracks at M 23 C 6 /δ interfaces within decomposed δ-ferrite ahead of the crack tip provide viable path for crack propagation, thus the fatigue crack growth resistance of δ-ferrite decreases. FF sample (nearly free of δ-ferrite) and CF sample (containing ∼4% δ-ferrite) were prepared from the AISI 316 austenitic stainless steel plate to elucidate the role of δ-ferrite in the fatigue crack growth under the solution treated and accelerated aged conditions. It is found that the fatigue crack growth resistance of the CF sample is higher than the FF sample under the solution treated condition. However, a significant deterioration of the fatigue crack growth resistance is observed in the CF sample while little variation is found in the FF sample after accelerated aging treatment at 750 °C for 10 h. In the solution treated condition, deflected crack growth path is present when the main crack encounters the δ-ferrite in the CF sample due to the differences in the fatigue responses between austenite and δ-ferrite. The measured growth rate of the deflected crack is significantly slower than that of the flat crack of the same length. After the accelerated aging treatment, microcracks are produced at the M 23 C 6 /δ interface due to the strain incompatibility between M 23 C 6 and retained δ-ferrite when the decomposed δ-ferrite is subject to plastic deformation in the crack tip plastic zone. The preexisting microcracks in the front of crack tip provide a viable path for crack propagation, resulting in the relatively flat crack path. [Display omitted] [ABSTRACT FROM AUTHOR]

• Cu-bearing austenitic stainless steel inhibits reproduction and adhesion of dominant bacteria in rich nutrient environment. • The increase of physical and chemical indexes including pH, TVB-N and nitrite contents results from food spoilage microorganism is weakened by Cu-bearing austenitic stainless steel. • The shelf life of produce and meat is extended by Cu-bearing austenitic stainless steel effectively. Food spoilage induced by microorganism leads to economic loss and is also a serious hazard to human health. The development of food preservation utensils with self-cleaning and antibacterial property is of great significance for interrupting the transmission of microorganism. In this study, we have simulated food preservation environment and studied a Cu-bearing austenitic stainless steel with different time to evaluate the effect of Cu on food preservation. The shelf life of food was extended to a certain extent by weakening the increased speed of physical and chemical indexes and deterioration degree of food morphology characteristics caused by microorganism. Furthermore, based on the antibacterial analysis results, Cu-bearing austenitic stainless steel inhibited reproduction of dominant bacteria in the rich nutrient environment. Thus, the Cu-bearing stainless steel reduced bacterial adhesion to the surface of the material and slowed the occurrence of food spoilage. The study provides evidence for application of Cu-bearing austenitic stainless steel in the area of food preservation. [ABSTRACT FROM AUTHOR]

• B improves hot ductility of S32654 at 850–1150 °C but worsens that at 1200–1250 °C. • B segregation at GB detected by APT was the main reason affecting hot ductility. • B segregation inhibits Mo segregation and then σ phase precipitation at 900–950 °C. • B segregation promotes nucleation and inhibits growth of DRX grain at 1100–1150 °C. • B segregation enhances the liquefaction cracking tendency at 1200–1250 °C. Influence mechanism of B segregation on the microstructure evolution and hot ductility of S32654 at 850–1250 °C was systematically investigated through experimental research and theoretical calculation. The results demonstrated that the segregation of B at grain boundary (GB) played different roles in the microstructure evolution and hot ductility at various temperatures. At 850 °C, B segregation inhibited Mo segregation at the GB and enhanced the GB cohesion. At 900–950 °C, B segregation restricted the diffusion and segregation of Mo to the GB, inhibiting the precipitation of σ phase. At 1000–1050 °C, B segregation accelerated the dislocation accumulation and limited the GB migration, promoting the nucleation and inhibiting the growth of DRX grains. At 1100–1150 °C, B has little effect on the DRX due to sufficient energy supply by higher temperature. Under the above beneficial effects of B, the hot ductility of S32654 was improved to varying degrees at 850–1150 °C. However, as the temperature increased to 1200–1250 °C, B segregation decreased the solidus temperature and enhanced the liquefaction cracking tendency, resulting in a deterioration of the hot ductility. [ABSTRACT FROM AUTHOR]

The article explores how mixing of salt water and different metals is sufficient to cause galvanic corrosion, and addition of electricity from onboard systems is a potent catalyst that can lead to highly destructive stray-current corrosion. Topics include common and avoidable sources of corrosion and the measures builders and service yards can take to minimize the risks; and different metals are placed differing electrical potentials will produce a voltage difference.

A patent has been issued for a headrest for a procedure chair and a procedure chair itself. The headrest includes a headrest backing, a cushion, a rail for supporting a diagnostic device, and an adapter for attaching to the procedure chair. The rail and adapter are made from austenitic stainless steel to reduce electromagnetic interference with the diagnostic device. The procedure chair also includes a backrest and an adapter for the headrest. The patent was filed by Chad Harris and assigned to Entellus Medical Inc. [Extracted from the article]

Predicting the mechanical behavior of polycrystalline materials containing a crack under both monotonic and cyclic loading conditions is crucial for accurately assessing the integrity of engineering materials. This study focuses on the deformation characteristics of face-centered cubic (fcc) grains within the crack tip field and their significant role in governing the driving force for fatigue crack growth during cyclic loading. We employ a cyclic crystal plasticity finite element (CPFE) model to analyze the mechanical response of austenitic 316L stainless steel polycrystals by accounting for nonlinear kinematic hardening effects. Through CPFE simulations, we investigate the deformation fields in 316L grains at the crack tip, considering two different grain orientations under plane strain conditions. Our CPFE results under monotonic loading align consistently with previous theoretical and experimental findings, particularly in comparing CPFE-simulated and experimentally observed plastic sectors consisting of different slip traces on the specimen surface near the crack tip. Based on a critical plastic work criterion for crack advancement, cyclic CPFE simulations are used to determine the fatigue crack growth rate as a function of stress intensity factor range for the two crack tip grain orientations in stainless steel. The simulated Paris law exponent matches experimental values. Furthermore, we compare cyclic CPFE results with those from cyclic J 2 plasticity finite element simulations. This study demonstrates a cyclic CPFE approach for determining crack tip fields, accounting for crystallographic effects on plastic deformation of crack tip grains. Our approach can be applied to effectively evaluate fatigue crack growth rates in fcc polycrystalline metals. [ABSTRACT FROM AUTHOR]

This work investigates the heterogeneous deformation and failure of HR3C austenitic stainless steel welded joints at room and typical service temperatures. Such types of welded joints are widely used in the new generation of fossil fuel power stations and are known to suffer from premature high temperature failure. Observation of in-service failures revealed that cracks may nucleate either in the heat affected zone or in the weld metal. The main objective of this work is to identify the local microstructural conditions and stress–strain fields responsible for both ductile failure and micro-crack nucleation within the weldment at low and high temperatures, respectively. To that purpose, a novel multi-scale micromechanics-based modelling framework is proposed. It relies on representative weld microstructure models digitally reconstructed from electron backscatter diffraction measurements, and dislocation density-based crystal plasticity models to describe the behaviour of individual grains in each weld region. A novel thermo-dynamically consistent relation for the configuration stored energy per unit volume is derived from the crystal plasticity framework. The single crystal models are calibrated and validated from a combination of uniaxial tensile tests on cross-weld specimens using high resolution digital image correlation techniques, representative volume elements of the polycrystals at the macro-scale, as well as micropillar compression tests at the scale of the individual grains. Predictions of heterogeneous inelastic deformation fields within the weldment at both 22 °C and 665 °C, and of micropillar compression behaviour of the individual weld single crystal phases are consistent with experimental data. The experimentally observed ductile failure of the weld metal at room temperature is successfully predicted using a Gurson-type void nucleation, growth and coalescence constitutive model. The suitability of the stored strain energy density and the accumulated plastic strain as crack initiation/creep failure indicators is investigated. It was found that predicted creep lifetimes with either indicator were very similar, and that they were relatively accurate for low stress levels. [ABSTRACT FROM AUTHOR]

A patent has been issued for a high-modulus alloy for medical devices. The patent, filed by inventors Rodney Ballard, James Davidson, and William Rezach, describes a biocompatible refractory-metal-based alloy with an elastic modulus above 300 GPa. The alloy includes tungsten, molybdenum, and niobium, and is free of rhenium, cobalt, nickel, and iron. The medical device can be used for various applications, including spinal implants, stents, dental implants, and orthopedic devices. The patent was assigned to Warsaw Orthopedic Inc. [Extracted from the article]

• Ce addition could modify MgO and MnS into Ce 2 O 3 and Ce 2 O 2 S in S32654. • Ce addition leads to noticeable refinement of both dendrite structure and σ phase. • Effective Ce-bearing inclusions could serve as nucleation cores of γ and σ phase. • Solute Ce markedly enhances undercooling degree, further refining dendrite structure. • Solute Ce promotes σ phase nucleation, while dendrite refinement limits its growth. The influence of Ce addition on the solidification structure and σ phase of super austenitic stainless steel S32654 was systematically investigated via microstructural characterization and thermodynamic calculation. The results indicate that a small addition of Ce could modify MgO and MnS into Ce-bearing inclusions Ce 2 O 3 and Ce 2 O 2 S. Ce addition led to noticeable refinement of both the dendrite structure and σ phase. The refinement mechanism could be attributed to the combined actions of effective Ce-bearing inclusions and solute Ce. Effective Ce-bearing inclusions could serve as heterogeneous nucleation cores of austenite as well as σ phase, which provided a favorable prerequisite for their refinement. Solute Ce significantly enhanced the undercooling degree of the system, further promoting dendrite structure refinement. Meanwhile, solute Ce improved the eutectic precipitation conditions of σ phase and further promoted its nucleation, while the dendrite refinement limited its growth space. Finally, more fine and dispersed σ phase particles formed in S32654 with Ce addition. The refinement of dendrite structure and σ phase will reduce the temperature and time required for high-temperature homogenization, which is beneficial to the hot working of this steel. [Display omitted] [ABSTRACT FROM AUTHOR]

• Stress relaxation cracking in Super304H austenitic stainless steel weld metal. • The pre-compressed CT technique combined with FEM analysis was successfully used. • The mechanism responsible for stress relaxation cracking formation was illustrated after short-term aging and long-term aging. The pre-compressed CT technique was used to quantitatively investigate the formation of stress relaxation cracks under different tensile residual stresses and aging time in Super304H austenitic stainless steel weld metal. The statistical results revealed that intergranular cracks could occur within 2000 h under 650 °C when the residual stress was applied with greater than 18 KN pre-compression force. Detailed grain interior and boundary analyses showed that the growth of intragranular Cu-rich particles could induce a strong grain interior, and the intergranular Nb(C, N) carbides were one of the causes to crack under short-term aging time. For long-term aging time conditions, the intergranular M 23 C 6 carbides were more susceptible to crack than intergranular Nb(C, N) carbides. Finally, the mechanism responsible for stress relaxation cracking formation was carefully illustrated for the weld metals after short-term aging and long-term aging, respectively. [Display omitted] [ABSTRACT FROM AUTHOR]

Bimetallic additively manufactured structures (BAMSs) can replace traditionally-fabricated functionally-graded-components through fusion welding processes and can eliminate locally-deteriorated mechanical properties arising from post-processing. The present work fabricates a BAMS by sequentially depositing the austenitic stainless-steel and Inconel625 using a gas-metal-arc-welding (GMAW)-based wire + arc additive manufacturing (WAAM) system. Elemental mapping shows a smooth compositional transition at the interface without any segregation. Both materials being the face-center-cubic (FCC) austenite, the electron backscattered diffraction (EBSD) analysis of the interface shows the smooth and cross-interface-crystallographic growth of long-elongated grains in the <001> direction. The hardness values were within the range of 220–240 HV for both materials without a large deviation at the interface. Due to the controlled thermal history, mechanical testing yielded a consistent result with the ultimate tensile strength and elongation of 600 MPa and 40 %, respectively, with the failure location on the stainless-steel side. This study demonstrates that WAAM has the potential to fabricate BAMS with controlled properties. [ABSTRACT FROM AUTHOR]

In this study, crevice corrosion performances of a newly developed LDSS 2002 and three commercial stainless steels (AISI 304, AISI 316L and DSS 2205) were investigated and discussed. Crevice repassivation potential (E R,CREV), which was measured by the potentiodynamic-galvanostatic-potentiodynamic (PD-GS-PD) test, was applicable to crevice corrosion evaluation of 304 and 316L stainless steels. However, much lower E R,CREV values were obtained for DSS 2205 and LDSS 2002. These abnormal E R,CREV values for duplex stainless steels may be related to the selective attack of the less corrosion-resistant phase, the lower corrosion potential in the crevice-like solution, and more crevice corrosion sites in the PD-GS-PD test. A critical chloride concentration of crevice corrosion (CCC CREV) measurement was introduced for crevice corrosion evaluation of various stainless steels. The derived CCC CREV was proved to be a valid criterion for crevice corrosion evaluation of both the austenitic and duplex stainless steels. An order of crevice corrosion resistance of AISI 304 ≈ LDSS 2002 < AISI 316L < DSS 2205 was suggested, which agreed well with the orders of pitting resistance equivalent number and critical crevice index of the less corrosion-resistant phase in each material. [ABSTRACT FROM AUTHOR]

The NiCrAlTi coatings free of N and with N incorporations were deposited on austenitic stainless steel 304L by magnetron sputtering in Ar and in gas mixture of Ar and N 2 , respectively. The N incorporated in the coatings existed as nitride precipitates (from ∼3 vol.% to ∼17 vol.%) after vacuum annealing. All the NiCrAlTi coatings, whatever free of N or with N incorporations, exhibited better resistance against cavitation erosion than ion plating TiN coating and the substrate 304 L in ultrasonic cavitation tests. The NiCrAlTi coating free of N incorporation presents superior cavitation erosion resistance. However, the nitrogen incorporation within the NiCrAlTi coatings showed negative effects on the resistance against cavitation erosion. [ABSTRACT FROM AUTHOR]

The article report on the humble hose clamps which are essential to the integrity of hulls and onboard systems, and their reliability depends on informed selection and best installation practices. It mentions that the hose clamps are vital to the operation of almost any vessel, and while they seem a mundane bit of inexpensive hardware, mistakes in choosing and installing them can be very costly.

The microstructures and stress-controlled fatigue behavior of austenitic stainless steel (AISI 316 L stainless steel) fabricated via laser-powder bed fusion (L-PBF) technique were investigated. For L-PBF process, zigzag laser scanning strategy (scan rotation between successive layer was 0°, ZZ sample) and cross-hatching layer scanning strategy (scan rotation between successive layer was 67°, CH sample) were employed. By inducing different thermal history, it is found that the scan strategies of laser beam have a significant impact on grain size and morphology. Fatigue cracks generally initiated from persistent slip bands (PSBs) or grain boundaries (GBs). It is observed that PSBs could transfer the melt pool boundaries (MPBs) continuously. The MPBs have better strain compatibility compared with grain boundaries (GBs), thus MPBs would not be the initiation site of fatigue cracks. A higher fatigue limit strength could be achieved by employing a crosshatching scanning strategy. For the CH sample, fatigue cracks also initiated from GBs and PSBs. However, fatigue crack initiated from process-induced defects were observed in ZZ sample in high-cycle regions. Solidification microstructures and defects characteristics are important factors affecting the fatigue performance of L-PBF 316 L stainless. Process-induced defects originated from fluid instability can be effectively reduced by adjusting the laser scan strategy. [ABSTRACT FROM AUTHOR]

The influence of N on the precipitation behavior, associated corrosion, and mechanical properties of S32654 were investigated by microstructural, electrochemical, and mechanical analyses. Increasing the N content results in several alterations: (1) grain refinement, which promotes intergranular precipitation; (2) a linear increase in the driving force for Cr 2 N and Mo activity, which accelerates the precipitation of intergranular Cr 2 N and π phase, respectively; (3) a linear decrease in the driving force for σ phase and Cr activity, which suppresses the formation of intragranular σ phase. The total amount of precipitates first decreased and then increased with the N content increasing. Furthermore, the intergranular corrosion susceptibility depended substantially on the total amount of precipitates and also first exhibited a decreasing and then an increasing trend as the N content increased. In addition, aging precipitation caused a considerable decrement in the ultimate tensile strength (UTS) and a remarkable increment in the yield strength (YS). Both the UTS and YS always increased with N content increasing throughout the solution and aging process. Whereas the elongation was considerably sensitive to the aging treatment, it exhibited marginal variation with the N content increasing. [ABSTRACT FROM AUTHOR]

We report that 316L austenitic stainless steel fabricated by direct laser deposition (DLD), an additive manufacturing (AM) process, have a higher yield strength than that of conventional 316L while keeping high ductility. More interestingly, no clear anisotropy in tensile properties was observed between the building and the scanning direction of the 3D printed steel. Metallographic examination of the as-built parts shows a heterogeneous solidification cellular microstructure. Transmission electron microscopy observations coupled with Energy Dispersive X-ray Spectrometry (EDS) reveal the presence of chemical micro-segregation correlated with high dislocation density at cell boundaries as well as the in-situ formation of well-dispersed oxides and transition-metal-rich precipitates. The hierarchical heterogeneous microstructure in the AM parts induces excellent strength of the 316L stainless steel while the low staking fault energy of the as-built 316L promotes the occurrence of abundant deformation twinning, in the origin of the high ductility of the AM steel. Without additional post-process treatments, the AM 316L proves that it can be used as a structural material or component for repair in mechanical construction. [ABSTRACT FROM AUTHOR]

A nanotwinned 316L austenitic stainless steel was prepared by means of surface mechanical grinding treatment. After recovery annealing, the density of dislocations decreases obviously while the average twin/matrix lamella thickness still keeps in the nanometer scale. The annealed nanotwinned sample exhibits a high tensile yield strength of ∼771 MPa and a considerate uniform elongation of ∼8%. TEM observations showed that accommodating more dislocations and secondary twinning inside the nanotwins contribute to the enhanced ductility and work hardening rate of the annealed nanotwinned sample. [ABSTRACT FROM AUTHOR]

A recent study conducted at Bialystok University of Technology in Poland investigated the bioactivity, cytotoxicity, and tribological properties of a nickel-free austenitic stainless steel produced through mechanical alloying and hot isostatic pressing. The researchers found that applying heat treatment after hot isostatic pressing reduced the friction coefficient and wear rate of the steel. Additionally, an immersion test in a simulated body fluid showed that the tested material was biocompatible and did not have significant toxic effects on human osteosarcoma cells. This research provides valuable insights into the development of nickel-free stainless steel for various applications. [Extracted from the article]

The price of austenitic stainless steel scrap in the UK and Europe was expected to come under significant pressure in the coming weeks because of downtrends in the nickel and molybdenum markets, as well as expectations that mills will take lower tonnages in December, market sources told Fastmarkets on Friday November 17. [ABSTRACT FROM AUTHOR]

Dissimilar high-energy beam (HEB) welding is necessary in many industrial applications. Different composition of heat-affected zone (HAZ) and weld metal (WM) lead to variation in mechanical properties within the dissimilar joint, which determines the performance of the welded structure. In the present study, appropriate filler material was used during electron beam welding (EBW) to obtain a reliable dissimilar joint between reduced-activation ferritic-martensitic (RAFM) steel and 316 L austenitic stainless steel. It was observed that the layered structure occurred in the weld metal with 310S filler (310S-WM), which had the inferior resistance to thermal disturbance, leading to severe hardening of 310S-WM after one-step tempering treatment. To further ameliorate the joint inhomogeneity, two-step heat treatment processes were imposed to the joints and optimized. δ-ferrite in the layered structure transformed into γ-phase in the first-step normalizing and remained stable during cooling. In the second-step of tempering, tempered martensite was obtained in the HAZ of the RAFM steel, while the microstructure of 310S-WM was not affected. Thus, the optimized properties for HAZ and 310S-WM in dissimilar welded joint was both obtained by a two-step heat treatment. The creep failure position of two dissimilar joints both occurred in CLAM-BM. [ABSTRACT FROM AUTHOR]

The effect of grain size (in the range from 4 μm to 12 μm) on the hydrogen embrittlement (HE) of 304 austenitic stainless steel (ASS) was studied. HE susceptibility result shows that HE resistance increases with grain refinement. Electron backscattered diffraction kernel average misorientation (EBSD-KAM) mapping shows that the strain localization can be mitigated by grain refinement. Hence, strain localization sites which act as highways for hydrogen diffusion and preferred crack initiation sites can be reduced along with grain refinement, leading to a high HE resistance. Meanwhile, grain size shows no influence on the strain induced martensite (SIM) transformation during the hydrogen charging slow strain tensile test (SSRT). Hence, the SIM formed during hydrogen charging SSRT is not responsible for the different HE resistance of 304 ASSs with various grain sizes. Hydrogen diffusion is supposed to be controlled by a competition between short-circuit diffusion along random grain boundary (RGB) and hydrogen trapping at dislocations, leading to a maximum hydrogen diffusion coefficient in the 304 ASS with an average grain size of 8 μm. [ABSTRACT FROM AUTHOR]

Corrosion is a foremost problem in many industries. In the petrochemical industry it impacts the equipment and assets of refineries and other facilities. Uncontrolled corrosion can cause leaks and component failures, bringing about a reduction in both the performance and reliability of important equipment. Corrosion can lead to unexpected failures that can be costly in terms of repair costs, environmental damage, and potential harm to humans. Chloride stress corrosion cracking (CI-SCC) behavior of stainless steel (SS) was investigated in a chloride environment at ambient temperature. This study aims to understand the mechanism of increased CI-SCC susceptibility of machined Type 304L SS (UNS S30403) in a chloride environment. [ABSTRACT FROM AUTHOR]

The article offers insights on the corrosion of stainless steel in marine environments. Topics discussed include the factors which influence the crevice corrosion mechanism like the shape of the crevice, environmental and temperature considerations, a case pertaining to the corrosion of stainless steel fittings in a private swimming pool and remedies with regard to the matter.

The price of austenitic stainless steel scrap in the UK and Europe increased in the week to Friday September 8, amid tight availability and optimism for better demand in the fourth quarter, sources told Fastmarkets. [ABSTRACT FROM AUTHOR]

In doing so, however, the resulting suture needle is not as strong as suture needles made from more commonly used materials (e.g., 455, 420, 300 series alloys or custom alloys such as tungsten-rhenium alloys), and thus the suture needle is not optimal for subsequent suturing procedures. "In one embodiment, the suture needle disclosed herein preferably has greater strength than a suture needle made entirely of a highly elastic material (e.g., nitinol), and the suture needle has a strength that entirely suitable for use in suturing tissue." The composite suture needle as claimed in claim 9, wherein said curved midsection and said sheath overlying said curved midsection define a flexible region of said composite suture needle that is more elastic than said curved proximal body section and said curved distal body section of said elongated body of said composite suture needle. [Extracted from the article]

A gradient nano-grained (GNG) surface layer was fabricated on an AISI 316L stainless steel (SS) by using the surface mechanical rolling treatment (SMRT). Reciprocating dry and oil-lubricated sliding tests of the GNG 316L SS in air at room temperature were conducted in comparison with the coarse-grained (CG) counterpart. Worn surface morphologies and subsurface microstructures were investigated for both 316L SS samples. 316L SS with a GNG surface layer shows a significantly improved wear resistance, especially under oil-lubricated condition. The notably wear resistance enhancement of the GNG 316L SS is attributed to the GNG surface layer with high strain accommodation ability and high hardness, which can reduce the wear volume in the running-in stage effectively. [ABSTRACT FROM AUTHOR]